Electrician has use flexi cable for boiler installation.

[RigidRaider]

Running several metres from boiler to cylinder cupboard and relays, he has used white flexible cable rather than grey 2 core + earth as I would expect. He has also joined the black cable from the Y plan motorised valve into this wiring using simple crimped connectors within the plastic conduit, where I would expect to find a proper juction box.

Should I get him back to put this right?

 

[electronicsuk]

It sounds fine to me, there's nothing wrong with using flexible cables for fixed wiring (even though we don't tend to do it), and crimps inside conduit or trunking are a perfectly acceptable method of making a concealed joint.

 

[Lectrician]

Crimps are not meant to be inside cable containment, just enclosures.

Using flex is not generally considered good practice, but plumbers seem to love it.

 

[RigidRaider]

I expect he did it for the same reason the plumber used flexible plastic pipes for the new primary circuit from boiler to cylinder.

 

[electronicsuk]

Crimps are not meant to be inside cable containment, just enclosures.

Is there any regulation that states this? I appreciate it's not good practice, especially if someone tries to pull back the cable through the conduit in the future, but the fact remains that crimps are an acceptable form of joint for use in inaccessible locations.

 

[RMS]

Don't see a problem with using crimp connectors in conduit. Although I would only expect this would be carried out when repairing a damaged cable where replacing it is out of the question.

However its not best practice on a new wiring install. With regards to BS7671, don't think there is any regulation that does not allow this. The integrity of the sheathing has been maintained by the conduit and a crimp compression connection does not have to be accessible.

 

[AndyPRK]

it does seam to be the norm for boiler thermostats etc to be wired in flex.

They even make special 5 core cable for it.

I was only wondering the other day whether it was still acceptable

 

[sparkyspike]

The trouble with using flat t+e or 3+e cable is that to wire up some boiler systems, you would need to use several cores and since you cannot use the CPCs (other than as CPCs), you will be wasting the bare wire. 5-core flex is often used to avoid having to use multiple runs of flat cable. If you have a programmer, room stat and boiler in one location, and cylinder stat, motorised valves and main isolator in another location, you could require up to 10 cores.

Regarding the crimp connections - although nothing actually wrong with this, electricians normally use a wiring centre or junction box for terminating valve leads.

 

[comms]

Nothing wrong with using flex for the heating circuit/controls..........I use 6 core for just such occations ( the supply from the DB I use 1.5 or 2.5mm T/E to a fused spur)

 

[ColJack]

526.5 - Every joint in a live conductor or a PEN conductor shall be made within one of the following or a combination thereof:

(i) A suitable accessory complying with the appropriate product standard
(ii) An equipment enclosure complying with the appropriate product standard
(iii) An enclosure partially formed or completed with building material which is non-combustible when tested to BS 476-4

 

[Lectrician]

What is the definition of an enclosure printed in the regs?

Is the definition of containment given?

 

[ColJack]

Enclosure - A part providing protection of equipment against certain external influences and in any direction providing basic protection.

no definition given for containment.

 

[securespark]

So if an enclosure is something that protects equipment, then trunking is an enclosure.

 

[ColJack]

trunking is a different animal to conduit though.. and the OP is talking about conduit..

if it's in trunking then the lid can be removed for getting at or around the crimps..

 

[electronicsuk]

trunking is a different animal to conduit though.. and the OP is talking about conduit..

if it's in trunking then the lid can be removed for getting at or around the crimps..

Seems to me that you're interpreting the regs to read what you want to read. There's no reason that an enclosure must have a removeable lid.